NASA's Unmanned Global Hawk Aircraft Makes First Science Flight

The
flight, the first of five scheduled for this month, is part of the Global
Hawk Pacific (GloPac) mission, intended to study atmospheric science over
the Pacific and Arctic oceans.

NASA?s
Global Hawk
is a robotic plane that can fly autonomously to altitudes above 60,000 feet
(18.3 kilometers)  roughly twice as high as a commercial airliner  and as far
as 11,000 nautical miles (20,000 kilometers)  half the circumference of Earth.

In
Wednesday's flight, the plane flew approximately 4,500 nautical miles (8,300
kilometers) along a flight path that took it from Dryden to just south of
Alaska's Kodiak Island, at 150.3 degrees West longitude and 54.6 degrees North
Latitude.

The
flight lasted a total of 14.1 hours, and the plane reached heights of up to
60,900 feet (18.6 kilometers) in altitude.

The
aircraft
system carries 11 instruments to sample the chemical composition of Earth's
two lowest atmospheric layers, to profile the dynamics and meteorology of both,
and to observe the distribution of clouds and aerosol particles. Project
scientists hope to take observations from the equator to the Arctic Circle, and
also west of Hawaii.

"The
Global Hawk is a fantastic platform because it gives us expanded access to the
atmosphere beyond what we have with piloted aircraft," said David Fahey,
co-mission scientist and research physician at NOAA's Earth System Research
Laboratory in Boulder, Colo. "We can go to regions we couldn't reach or go
to previously explored regions and study them for extended periods that are
impossible with conventional planes."

Self-piloting

NASA
pilots and flight engineers, working with colleagues from the National Oceanic
and Atmospheric Administration (NOAA), pre-program a flight path, after which
the Global Hawk flies itself for up to 30 hours, staying in contact through
satellite and line-of-site communications to the ground control station at
NASA's Dryden Flight Research Center in California's Mojave Desert.

The
aircraft can take off, fly its mission and land without any pilot or scientist
intervention. Though the plane is designed to fly on its own, pilots can change
course or altitude based on the atmospheric conditions. Researchers have the ability
to command and control their instruments from the ground.

"The
Global
Hawk is a revolutionary aircraft for science because of its enormous range
and endurance," Paul Newman, co-mission scientist for GloPac and an
atmospheric scientist from NASA's Goddard Space Flight Center in Greenbelt, Md,
said in a statement. "No other science platform provides this much range
and time to sample rapidly evolving atmospheric phenomena."

The
mission is also an opportunity to demonstrate the unique capabilities of the
Global Hawk, while also gathering atmospheric data in a region that has
until now been poorly sampled, he added.

GloPac
researchers will measure and sample greenhouse gases, ozone-depleting
substances, aerosols, and constituents of air quality in the upper troposphere
and lower stratosphere.

GloPac
flights should also allow scientists to observe the breakup of the polar
vortex, a large-scale cyclone that dominates winter weather patterns around the
Arctic and is especially important for understanding ozone depletion in the
Northern Hemisphere.

Sampling the atmosphere

Researchers
have already gathered some measurements from the polar vortex from Wednesday's
flight.

Scientists
also expect to gather data between 45,000 and 65,000 feet (almost 14,000 and
20,000 meters), where many greenhouse gases and ozone-depleting substances are
destroyed. This will help researchers measure dust, smoke and pollution that
cross the Pacific from Asia and Siberia that affect U.S. air quality.

Several
instruments will measure aerosols, which play an important but incompletely
understood role in Earth's energy budget. Some aerosols absorb warming
sunlight, while others reflect it back to space and cool the planet. High-altitude
particles can serve as nuclei for the formation of clouds.

GloPac
will make several flights directly under the path of NASA's Aura satellite and
other Earth-observing satellites, "allowing us to calibrate and confirm
what we see from space," Newman said. GloPac missions are being conducted
in conjunction with NASA's Aura Validation Experiment (AVE).

During
its first science flight, the Global Hawk flew under the Cloud-Aerosol LIDAR
and Infrared Pathfinder Satellite Observation (CALIPSO), a joint project of
NASA and France's Centre National d'Etudes Spatiales.

The
Global Hawk was originally flown in the Advanced Concept Technology
Demonstration program sponsored by the Defense
Advanced Research Projects Agency. Two test models were transferred from
the U.S. Air Force to NASA in 2007, and a third was transferred in 2009.